Tualatin River samples safe for water recreation, federal agency finds

A blue-green algae bloom that has laced an 11-mile stretch of the Tualatin River between Sherwood and Lake Oswego has remained below safety standards for water recreation, the U.S. Geological Survey said tonight.

The agency's office in Portland received test results on whether the algae pose a hazard for drinking water or water-contact activities. Samples were taken Wednesday from the river at Cook Park, Stafford Road and Jurgens Park.

The levels at all three sites were rated safe for recreation under World Health Organization standards, said Stewart Rounds, an agency spokesman. Only Jurgens Park had levels considered risky for drinking water.

However, Rounds cautioned that the toxin levels may change. "It still seems prudent to avoid areas of the river that have a visible floating mat of algae," he said.

The clumpy algae were first spotted by Roy Rogers Road near Sherwood on Monday before traveling downstream as far as Stafford Road near Lake Oswego. They were most pronounced near Tigard and Tualatin and were akin to clam chowder Wednesday near Jurgens Park in Tualatin, said Brian Wegener, a watershed watch coordinator for Tualatin Riverkeepers.

Blue-green algae, despite the common name, are not algae but a type of bacteria that turn sunlight into energy. A bloom occurs when algae multiply rapidly.